Effects of forest floor coverage on overland flow and soil erosion on hillslopes in Japanese cypress plantation forests
Effects of forest floor coverage on overland flow and soil erosion on hillslopes in Japanese cypress plantation forests
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DOI：
10.1029/2008wr007270
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发表时间：
2009-06
影响因子：
5.4
通讯作者：
S. Miyata;K. Kosugi;T. Gomi;T. Mizuyama
中科院分区：
文献类型：
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作者：
S. Miyata;K. Kosugi;T. Gomi;T. Mizuyama
研究了不同盖度条件下成熟柏树人工林地表径流和土壤侵蚀的影响，包括稀疏林下枯枝落叶层(裸露地块)、密植蕨类植物林下和枯枝落叶层(盖层地块)，以及对盖层地块(移除地块)进行植被地被移除试验。我们测量了土壤水力特性，并监测了三个重复的地块(每个约1×2米)的坡面径流和土壤侵蚀，分别代表未覆盖、覆盖和清除条件。由于表层土壤的很强的排水性，即使在有盖子的地块上也会发生大量的陆上径流。然而，覆盖地块的年地表径流量是未覆盖地块的37%。裸地年土壤侵蚀量是覆盖地的3.7倍。除草样地的坡面径流与裸地相似，但前者的土壤侵蚀量明显大于后者。这些结果表明，样地之间土壤可蚀性的差异是侵蚀的基本决定因素，其重要性不亚于地面盖度。我们独立地量化了地面复盖度和土壤可蚀性的影响，并通过应用侵蚀模型检验了复盖度和侵蚀之间的关系。在覆盖小区中，与抑制地表径流和泥沙输送相比，地面覆盖阻止了95%的土壤雨滴剥离，这是减少土壤侵蚀的主要机制。覆盖地块的土壤可蚀性是未覆盖地块的4.5倍。这意味着，简单地比较不同复盖条件的样地不足以检验植被复盖对土壤侵蚀的影响。
We examined the effects of forest floor coverage on overland flow generation and soil erosion in mature Japanese cypress plantations with different coverage conditions: sparse understory and litter (uncovered plots), dense fern understory and litter (covered plots), and experimental removal of vegetative floor coverage on the covered plots (removal plots). We measured soil hydraulic properties and monitored overland flow and soil erosion in three replicated plots (approximately 1 × 2 m each) representing uncovered, covered, and removal conditions. Because of the strong water repellency of the surface soil, a substantial amount of overland flow occurred, even in covered plots. Nevertheless, the annual overland flow in covered plots was 37% of that in uncovered plots. Annual soil erosion in uncovered plots was 3.7 times greater than that in covered plots. Although overland flow in removal plots was similar to that in uncovered plots, soil erosion in the former was significantly greater than in the latter. These results suggest that differences in soil erodibility between the plots were essential determining factors of erosion and were no less important than floor coverage. We quantified the effects of floor coverage and soil erodibility independently and examined the relationship between coverage and erosion by applying an erosion model. In covered plots, floor coverage prevented 95% of soil detachment by raindrops, which was the dominant mechanism in reducing soil erosion, as compared with it inhibiting overland flow and resisting sediment transport. The soil erodibility of plots with ground cover was 4.5 times higher than that of uncovered plots. This implies that simply comparing plots with different coverage conditions is not sufficient for examining the effects of vegetation coverage on soil erosion.